Abstract

Background

Hepcidin, a peptide that is released into the blood in response to inflammation, prevents
cellular iron export and results in declines in iron status. Elevated serum and urinary
levels of hepcidin have been observed in athletes following exercise, and declines
in iron status have been reported following prolonged periods of training. The objective
of this observational study was to characterize the effects of an occupational task,
military training, on iron status, inflammation, and serum hepcidin.

Findings

Volunteers (n = 21 males) included Norwegian Soldiers participating in a 7-day winter
training exercise that culminated in a 3-day, 54 km ski march. Fasted blood samples
were collected at baseline, on day 4 (PRE, prior to the ski march), and again on day
7 (POST, following the ski march). Samples were analyzed for hemoglobin, serum ferritin,
soluble transferrin receptor (sTfR), interleukin-6 (IL-6), and serum hepcidin. Military
training affected inflammation and serum hepcidin levels, as IL-6 and hepcidin concentrations
increased (P < 0.05) from the baseline to POST (mean ± SD, 9.1 ± 4.9 vs. 14.5 ± 8.4 pg/mL and
6.5 ± 3.5 vs. 10.2 ± 6.9 ng/mL, respectively). Iron status was not affected by the
training exercise, as sTfR levels did not change over the course of the 7-day study.

Conclusions

Military training resulted in significant elevations in IL-6 and serum hepcidin. Future
studies should strive to identify the role of hepcidin in the adaptive response to
exercise, as well as countermeasures for the prevention of chronic or repeated elevations
in serum hepcidin due to exercise or sustained occupational tasks which may result
in longer term decrements in iron status.